On Kaua'i, you can't walk the beach called Oneone at Wainiha without getting wet, and yet you can hear residential construction work from shore.

Owners have been doing new construction just a few dozen feet from where eroded sand drops from naupaka and heliotrope bushes into the wash of the waves. Coconut roots dangle out over the shoreline foam.

The looming crisis of Hawai'i's eroding beaches has not stopped new shoreline construction.

Owners are battling for the right to build new homes on sandy shorefront lots at the same time others are applying for emergency permits to install sandbags and concrete walls to protect existing residences.

Already, nearly the entire stretch of Lanikai Beach on O'ahu is "hardened" with seawalls. Other shorelines statewide aren't far behind.

"We've given out emergency sandbag permits on almost every island. O'ahu, Maui and Kaua'i are the big three," said Sam Lemmo, head of the state Department of Land and Natural Resources' Office of Conservation and Coastal Lands.

"We have at least a dozen requests for (permanent) seawalls, all over O'ahu," said Art Challacomb, acting chief of the city's Land Use Permits Approval Branch.

The problem with seawalls is that while they may protect one person's house, the larger public loses its beach.

"Some places in Lanikai, you're up to your chest in water" walking by a seawall where the beach used to be, Lemmo said.

Lemmo's office is beginning the process of planning for a statewide policy on protecting beaches, because he said the current system isn't working. But the issues are difficult, and the planning process is just starting, he said. Meanwhile, his office and those of other involved government agencies are doing crisis management.

"Recently, the city approved a couple of houses on postage-stamp properties on the beach on the North Shore. They're building it and it's already threatened," Lemmo said. "We don't understand why people want to build in harm's way. It's not rational."

Coastal activist Caren Diamond, a resident of Wainiha on Kaua'i, feels that many people developing shoreline property aren't worried about what might happen a few years down the road, because it will be someone else's problem.

"All these properties are for sale," she said, sweeping an arm toward the Wainiha-Ha'ena shoreline, where winter waves already splash into and under the foundations of many beachfront homes.

Challacomb says the city is trapped by existing codes. Property owners have a legal right to build on a residential lot, and the city feels compelled to let them protect the house with a seawall if there are no other viable options, he said.

But coastal erosion is not showing any signs of abating.

"If you look at predictions of sea level rise, we certainly need to be prudent about how we site houses," Diamond said. "There is no excuse for currently siting a house in danger."

Government's first line of defense has been to establish building setbacks — deciding where the legal shoreline is and then requiring people to build a certain distance back. On O'ahu, the setback was 40 feet, but for more than 10 years it has been 60 feet. On Maui, coastal engineers have determined which beaches are retreating fastest, and they set deeper setbacks there. Kaua'i is considering a similar rule. Big Island Planning Director Chris Yuen said his office sets deeper setbacks when it feels they are justified.

But many long-established coastal lots are shrinking with statewide shoreline retreat, and some property owners fight with government officials and environmental groups over where to establish the official shoreline, to gain more flexibility to site their homes.

If you own a piece of coastal land, before you can build you need a shoreline certification — a determination by surveyors of where the state-owned beach ends and private property begins. County building setbacks are calculated from that line. But establishing the location of the shoreline has long been an issue.

"The nature of a shoreline is that it's not static. It's dynamic," said state Surveyor Reid Siarot.

In June, the state Department of Land and Natural Resources established a rule that gives coastal vegetation and the debris line equal weight in identifying the location of the shoreline. But in some areas, the apparent debris line and vegetation line can be yards apart. On Kaua'i's rainy north shore, salt-tolerant plants thrive well makai of where the highest winter waves can reach.

Why would a property owner fight for the right for a more seaward line, even though it can put a home in a riskier location?

Wainiha property owner Joe Brescia, a California resident, said there's one simple reason: "Everybody wants to see the ocean if you have a beachfront lot," he said.

Attorney Walton Hong said the battle in his client Brescia's case is about practicality — if he builds as far back as some would require, there would not be enough room to meet building and setback requirements, put in a septic field and turn a car around on the property. But at this point, Hong said, Brescia would just like a decision — his request for a shoreline certification has been held up by environmental group appeals and departmental delays for nearly a year, and that's after previous certification expired.

"He's been trying to build his house since 2001," Hong said.

Brescia said it's a frustrating system that has cost him immense amounts of money in mortgage payments and legal fees.

"It's a very ponderous, almost labyrinthine system, and it's been very frustrating," he said. "I do believe DLNR is moving toward a more clearly defined set of rules."

Carl Stephens, a Ha'ena property owner and Washington state resident, said he eventually sold his beachfront property out of frustration. "You get the shoreline certified, and they appeal it, and by the time you go through the protests, your certification expires and you have to start over. My place is now being built, but I've since sold it. I was just tired of it," Stephens said.

Lemmo said long delays are isolated cases and he has heard few complaints about delays in recent months.

State officials say they're doing a better job of certifying shorelines than in past years, combining the skills of private surveyors with the state surveyor, a coastal geologist in Lemmo's office, and the reduced emphasis on the vegetation line as an indicator of where the high wash of the waves reaches.

"They're introducing a lot more scientific data and technology," said Dean Uchida, of the Land Use Research Foundation.

But attorney Bernard Bays said all the new approaches simply are creating headaches and unacceptable delays for some landowners. "Shoreline certification used to be a pretty routine process," and if it was a process that once favored landowners, now "the backlash has gone to the other extreme. Landowners have given up on getting any kind of advantageous shoreline."

Diamond said beachfront landowners continue to run irrigation lines to the edge of the shoreline to promote vegetation growth that reduces the size of the public beach. The irrigation, along with north Kaua'i's plentiful rainfall, can keep greenery growing well seaward of where waves wash in winter, she said.

Diamond said the naupaka, heliotropes, palms and other plants grown in this way limit the size of the public beach, and prevent the beach from expanding and contracting normally with the seasons.

"They are de facto vegetative seawalls. In times of high tides, you can't walk the beach any more," she said.

Uchida, whose foundation normally supports the rights of property owners, said the process of watering the public shoreline is unacceptable. "We're not supporting anybody who's inducing vegetation. That's just encroaching," Uchida said.

Lemmo said there may be multiple approaches to dealing with beach loss in the long term. In some cases it may be appropriate to dump or pump sand onto the most prized beaches to preserve them, a process called beach nourishment. In others, hardening might be the best alternative. Some properties might need to be abandoned to let the beach naturally move inland — and perhaps government will need to buy out some property owners.

In any case, he said, it is clear right now that new development, whether residential, highway or commercial, ought to be kept away from retreating coasts.

"It's not like people bought property and then the rules changed. We've known about coastal erosion for a long time," he said.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.